A control device of the type to which the invention relates comprises an actuator member (knob, pedal) suitable for pivoting about an axis on either side of a neutral position and for controlling a modification to the flying surfaces of the aircraft in terms of roll and/or pitch, and for this purpose it is capable of pivoting about two main axes that are perpendicular (Cardan joint type mount). Mechanical or hydraulic type control systems act in a structurally intrinsic manner to generate opposing forces that are perceived by the pilot on moving the stick. In contrast, in electrical or electronic control systems, no opposing force is generated naturally and it is necessary to add an auxiliary device associated with the main control specifically for generating an opposing force that can be perceived by the user, as a function of the angular displacement of the actuator member.
In some circumstances, it is necessary to make provision for the opposing force to differ in magnitude as a function of the position of the actuator member; for example, it can be desirable for the opposing force to be proportional to the angular offset of the actuator member over a major fraction of its stroke, but with an opposing force that becomes greater in the vicinity of the end of the stroke so that the pilot can “feel” the approaching end of the stroke. Such a control with opposing force that varies in stages can find a particular application in controlling pitch control surfaces. It may also be desirable to have, in addition, forces that are unequal depending on the direction in which the actuator member is displaced.